The characteristics of the pump determine that the self-priming capacity of the pump will not exceed 10m(because the atmospheric pressure is only 0.1mpa, and each pump has certain cavitation), the self-priming capacity of the general large pump will not exceed 5m, and the head of the self-priming pump is relatively low. And the most reliable sustainable water supply must be nearby rivers, sea, lake, reservoir, etc. There is a lot of water, where the car can reach and horizontal distance often is higher, ordinary trailer basic unable to absorb the water pump, because even a water absorption can be severe cavitation without the effect of water, can't do big supply water flow.

The set of units can drag pressure pump and hydraulic pump at the same time, through the hydraulic motor drive with float under the pump directly into the water surface (river or sea), through the hydraulic drive under the pump to pump water directly to the pressure pump, and then through the pressure pump to the place of use. The continuous operation power of the engine has ensured the continuous water supply until the machine is shut down to directly solve the problem of water supply for fire fighting application.